Speaking at around 1pm on Wednesday, he said: “The 10 boys will be dead in four hours [by this time tomorrow]. It is just a bad time. This time tomorrow the boys will all be dead.”

Asked what would help him secure closure, he replied: “The inquest. It needs to be finished.

“There seems to be an orchestrated attempt to delay it and delay it. Really the only person I trust in authority is the coroner and he seems to be running a pretty tight ship. So we are going to have to put all our trust in him because nobody else seems to want it.”

A match to a palm print on the getaway minibus was made just after the legacy inquest opened in May. The 59-year-old suspect was arrested in Newry in August but it is not yet known if he will be prosecuted. The legacy inquest remains officially suspended as a result.

Colin Worton, whose brother Kenneth was also killed, says the atrocity is a test case for other victims.

“If the authorities can’t work out this and get it solved it doesn’t really give anyone that has had one individual killed much confidence in the system,” he said.

The detective in charge, he said, had declined to tell him whether the PSNI had made any recommendation to the PPS about the palm print suspect. “I was not even asking what the recommendation was – so I have no confidence whatsoever in them.”

DCI Ian Harrison said that police are continuing “a number of inquiries” in relation to Kingsmills. The suspect arrested in August was released pending a report to the PPS “however it would not be appropriate to discuss the detail of this report”.

He added: “I acknowledge the concerns and frustrations felt by the families but I would reassure them we remain committed to supporting the ongoing inquest and playing our part in securing truth and justice for everyone involved.”